Asymmetric shielded two electrode cuff

• US 4,628,942 A
• Filed: 10/11/1984
• Issued: 12/16/1986
• Est. Priority Date: 10/11/1984
• Status: Expired due to Term

• Current Assignee: Case Western Reserve University
• Original Assignee: Case Western Reserve University
• Inventors: Mortimer, J. Thomas, Sweeney, James D.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Shein, Mitchell J.
• Application Number:
  US06/659,823
• Time in Patent Office: 796 Days
• Field of Search: 128/784-785, 128/642, 128/419 C, 128/802
• US Class Current: 607/118
• CPC Class Codes: A61N 1/0556 Cuff electrodes

Abstract

A nerve trunk (A) has an annular electrode cuff (B) positioned therearound for imposing electrical signals on to the nerve trunk for the purpose of generating unidirectionally propagated action potentials. The electrode cuff includes an annular cathode (30) having a circular passage therethrough of a first diameter. An annular anode (40) has a larger circular passage therethrough of a second diameter, which second diameter is about 1.2 to 3.0 times the first diameter. A non-conductive sheath (50) extends around the anode, cathode, and nerve trunk. The anode and cathode are placed asymmetrically to one side of the non-conductive sheath. Specifically, a first length (L1) along the electrode sheath between a first end (56) and the cathode is at least twice a second length (L2) between the anode and cathode. A third length (L3) between the anode and a second end (58) of the conductive sheath is smaller than the first or second lengths. With this geometry, the majority of the current applied to the anode electrode flows to the cathode along path segments (62b and 62d) with lesser amounts of current flowing in the path segments (64a), (64b), (66a), and (66b).

Claims

1. An electrode cuff for introducing unidirectionally propagated action potentials in a single direction on a nerve trunk, the cuff comprising:

a generally annular cathode defining a first passage therethrough of a first diameter;

a generally annular anode defining a second passage therethrough of a second diameter, the second diameter being 1.2 to 3.0 times as large as the first diameter such that the cathode is more proximate to the nerve trunk passing therethrough than the anode; and

,

an insulating shield extending from a first end thereof to the cathode, from the cathode to the anode, and from the anode to a second end thereof, a distance between the cathode and the first end being at least twice a distance between the cathode and the anode.

2. A nerve stimulator system for inducing unidirectionally propagating action potentials on a nerve trunk, the system comprising:

a two electrode cuff including;

a first annular electrode defining a first passage therethrough having a first diameter that is larger than the trunk diameter, a second annular electrode defining a second passage therethrough having a second diameter which is larger than the first diameter, an insulating electrical shield extending around the nerve trunk and the first and second electrodes, the insulating shield having a first length extending from a first end thereof to the first electrode, a second length between the first and second electrodes and a third length extending from the second electrode to a second end thereof, the first length being at least two times the combined second and third lengths such that the second electrode is closer to the second end than the first electrode is to the first end; and

,

a signal generator for applying an oscillatory signal to the first and second electrodes such that the first electrode is primarily biased as a cathode and the second electrode is primarily biased as an anode.